In a medium mixing bowl, whisk together the Bisquick baking mix, milk, egg, and vegetable oil until the batter is smooth.
Preheat your waffle iron and lightly grease it with non-stick spray or a dab of vegetable oil to ensure easy waffle removal.
Pour enough batter into the center of the hot waffle iron to just cover the waffle grid.
Close the lid and cook the waffle until it is golden brown and the steam has mostly stopped, about 5 minutes. Then, gently remove the waffle and serve immediately.